001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.jxpath.ri.compiler;
018
019import org.apache.commons.jxpath.ri.QName;
020import org.apache.commons.jxpath.ri.EvalContext;
021
022/**
023 * An element of the compile tree holding a variable reference.
024 *
025 * @author Dmitri Plotnikov
026 * @version $Revision: 652845 $ $Date: 2008-05-02 19:46:46 +0200 (Fr, 02 Mai 2008) $
027 */
028public class VariableReference extends Expression {
029
030    private QName varName;
031
032    /**
033     * Create a new VariableReference.
034     * @param varName variable name
035     */
036    public VariableReference(QName varName) {
037        this.varName = varName;
038    }
039
040    /**
041     * Get the variable name.
042     * @return QName
043     */
044    public QName getVariableName() {
045        return varName;
046    }
047
048    public String toString() {
049        return "$" + varName;
050    }
051
052    public boolean isContextDependent() {
053        return false;
054    }
055
056    public boolean computeContextDependent() {
057        return false;
058    }
059
060    public Object compute(EvalContext context) {
061        return computeValue(context);
062    }
063
064    /**
065     * Returns the value of the variable.
066     * @param context EvalContext against which to compute the variable's value.
067     * @return Object
068     */
069    public Object computeValue(EvalContext context) {
070        return context.getRootContext().getVariableContext(varName);
071    }
072}